Question

2. Which of the following nucleotide bases are BOTH pyrimidines?
A. cytosine and adenine
B. cytosine and guanine
C. thymine and guanine
D. uracil and adenine
E. cytosine and uracil​

Answer 1

Answer: E

Explanation: The correct answer is cytosine and uracil. A pyrimidines are aromatic and polar each with different chemical group.

Answer 2

Answer:

E. cytosine and uracil  

Explanation:

Pyrimidine is an aromatic compound similar to pyridine. The difference is that it has two nitrogen atoms at positions 1 and 3 in the ring.

The pyrimidine bases have the same six-membered ring structure with two N atoms at the 1,3-positions.

In addition, cytosine has a carbonyl and an amino group, while uracil has two carbonyl groups.